Some conventional apparatuses for mounting electronic parts include part cassettes for holding electronic parts which are carried on a moving table. The moving table is moved along a straight path to a predetermined pick up station where an electronic part is removed from the part cassette. Then the electronic part is mounted onto a substrate.
In order to increase the mounting speed of the electronic parts on the substrate, the speed of the transferring and mounting units for transferring and mounting electronic parts have been increased. In conventional apparatuses for mounting electronic parts, however, the speed of the units for feeding electronic parts, such as the moving table which positions a desired part cassette at a pick up station, is not as fast as the transferring and mounting units.
FIG. 11 and FIG. 12 illustrate the operation of a conventional apparatus for mounting electronic parts. In FIGS. 11 and 12, a plurality of part cassettes U1, U2, . . . , U8 accommodating respectively different types of parts are placed at pitches of `t` on a moving table 101. When a transferring and mounting head 102 is caused to come to a fixed stop at position 104 by the transferring and mounting unit, an electronic part is removed using nozzle 103 attached under the transferring and mounting head 102. As shown in FIG. 11, the electronic part is removed from the cassette U4 positioned at stop position 104.
Next, if an electronic part is to be removed from part cassette U5 using transferring and mounting head 102, as shown in FIG. 12, moving table 101 must move immediately in the X direction a moving distance of DO to position the part cassette U5 at stop position 104.
In the conventional apparatus above, when the transferring distance DO is large, or the moving table 101 is slow, the moving table 101 often does not complete its movement to the position shown in FIG. 12 by the time the transferring and mounting electronic unit completes one cycle.
Accordingly, the transferring and mounting electronic unit has to wait until the moving table 101 completes the determined movement, or skip the step. Accordingly, even if the transferring and mounting electronic unit operates at a high speed to improve the mounting speed, the operation speed of the apparatus may be limited due to the operation of moving table 101.